The present invention relates generally to row crop harvesting machinery and, more particularly, to an improved row unit frame structure.
Corn headers generally include individual row units normally designed for harvesting a single row of crop material. To accommodate various spacings between rows of crops, these row units are usually adjustably attached to a horizontally disposed frame member. The modern trend in corn headers appears to be one of placing the row units at a low profile to the ground and providing for increasingly larger capacity.
Row units are commonly constructed such that the frame is attachable to a gearbox corresponding to each individual row unit. The gearbox in turn is connected to the horizontally disposed frame member. Reference to such a construction can be had in U.S. Pat. No. 3,589,110.
However, this construction leads to several disadvantages. The row unit frame can become loosened from its mounting on the gearbox which leads to stability problems. The gearbox itself is usually a heavy expensively formed member which, since each corn header includes a plurality of row units, adds, not only to the weight, but also to the cost of the header. Additionally, the extra hardware and connecting means also increases both the weight and the cost of producing corn headers.
Some drive systems have attempted to do away with as much of the gearbox as possible and do not provide lubrication for some of the gears which drive the stalk rolls and/or the gathering chains; however, excessive wear and operating noise lead to the conclusion that such drive systems are less desirable. Moreover, such arrangements generally increase the distance from the end of the gathering chain to the consolidating auger which, in turn, increases the possibility of crop material clogging or plugging the row units with crop becoming lodged in this "dead" area.